1. Field of the Invention
This invention generally relates to a printer and in particular to a paper setting mechanism of a printer for setting a sheet of paper around a platen roller to be ready for printing. More specifically, the present invention relates to a mechanism for controlling the position of a paper bail assembly for keeping a sheet of paper pressed against the platen roller of a printer.
2. Description of the Prior Art
In general, in various types of printers, including type wheel printers, thermal printers, thermal transfer printers, dot-impact printers and electronic typewriters, when a sheet of paper is to be set in position, a paper bail assembly is moved to its retracted position separated away from a platen roller thereby allowing a sheet of paper to be set in position as placed around the platen roller, and, then, the paper bail assembly must be moved back to its set position where the bail rollers of the paper bail assembly are pressed against the platen roller with the sheet of paper sandwiched therebetween.
Thus, in such a prior art paper setting mechanism of a printer, the paper bail assembly is, for example, pulled manually in a predetermined direction so as to be temporarily retained at its retracted position where the bail rollers are separated away from the platen roller, and, after placing a sheet of paper around the platen roller, the paper bail assembly is further pulled in the predetermined direction to have a microswitch or the like activated thereby causing the platen roller to rotate over a predetermined amount in the normal direction whereby the sheet of paper placed around the platen roller is set in position, which is followed by the step of manually moving the paper bail assembly to the opposite direction to release the restrained condition of the paper bail assembly thereby causing the bail rollers to be pressed against the platen roller with the sheet of paper sandwiched therebetween to complete the paper setting operation. However, such a prior art paper setting mechanism is poor in operability because the paper bail assembly must be operated manually not only when a sheet of paper is to be inserted but also when the bail rollers are to be brought back to the set condition to be pressed against the platen roller.